export default {
	namespaced: true,

	state: () => ({
		// 购物车的数组，用来存储购物车中每个商品的信息对象
		// 每个商品的信息对象，都包含如下 6 个属性：
		// { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
		cart: JSON.parse(uni.getStorageSync('cart') || '[]')
	}),
	//mutations 方法
	mutations: {
		addToCart(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			console.log(findResult);

			if (!findResult) {
				state.cart.push(goods)
			} else {
				findResult.goods_count++
			}
			// console.log(state.cart);

			this.commit('m_cart/saveToStorage')
		},
		saveToStorage(state) {
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		//更新购物车中商品的勾选状态
		updateGoodsState(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)

			if (findResult) {
				findResult.goods_state = goods.goods_state

				this.commit('m_cart/saveToStorage')
			}
		},
		//更新商品的数量
		updateGoodsCount(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)

			if (findResult) {
				findResult.goods_count = goods.goods_count
				//持久化存储到本地
				this.commit('m_cart/saveToStorage')
			}

		},
		// 根据 Id 从购物车中删除对应的商品
		removeGoodsById(state, goods_id) {
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)

			this.commit('m_cart/saveToStorage')
		},
		//更新购物车中所有商品的勾选状态
		updateAllGoodsState(state,newState){
			state.cart.forEach(x=>x.goods_state = newState)
			
			this.commit('m_cart/saveToStorage')
		}
	},
	// getters 属性
	getters: {
		//购物车中所有勾选商品的总数量
		total(state) {
			// let c = 0
			// state.cart.forEach(x => c += x.goods_count)
			// return c
			
			return state.cart.reduce((total,item)=>total+=item.goods_count,0)
		},
		//购物车中已勾选的总数量
		checkedCount(state) {
		  // 先使用 filter 方法，从购物车中过滤器已勾选的商品
		  // 再使用 reduce 方法，将已勾选的商品总数量进行累加
		  // reduce() 的返回值就是已勾选的商品的总数量
		  return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
		},
		//已勾选商品的总价格
		checkedGoodsAmount(state){
			return state.cart.filter(x => x.goods_state)
			                   .reduce((total, item) => total += item.goods_count * item.goods_price, 0)
			                   .toFixed(2)
		}
	},
}